Mazegawa No.2 Dam (馬瀬川第二ダム, Mazegawa dai-ni da-mu) is a dam in the city of Gero in Gifu Prefecture, Japan on the Maze River. The dam is part of the Iwaya Dam project which acts as a flood control across the wider Kiso River system. The dam is a concrete gravity dam with a height of 44.5 meters. It was constructed for hydroelectric power generation and its associated power plant has a capacity of 288,000 kilowatts of power. It is managed by the Chubu Electric Power Company.